Maximum Output Power Level Research Articles

A Multimode/Multiband Power Amplifier With a Boosted Supply Modulator

A multimode/multiband power amplifier (PA) with a boosted supply modulator is developed for handset applications. A linear broadband class-F amplifier is designed to have a constant fundamental impedance across 1.7-2 GHz and its second and third harmonic impedances are located at the high-efficiency area. To reduce the circuit size for handset application, the harmonic control circuits are merged into the broadband output matching circuit for the fundamental frequency. An envelope-tracking operation delivers high efficiency for the overall power. The linearity is improved by envelope tracking (ET) through intermodulation-distortion sweet-spot tracking at the maximum output power level. The efficiency and bandwidth (BW) are enhanced by a boosted supply modulator. Multimode operation is achieved by an ET technique with a programmable hysteresis control and automatic switching current adaptation of the hybrid supply modulator. For demonstration purpose, the PA and supply modulator are implemented using an InGaP/GaAs heterojunction bipolar transistor and a 65-nm CMOS process. For a long-term evolution signal, the envelope-tracking (ET) PA delivers a power-added efficiency (PAE) and an error vector magnitude of 33.3%-39% and 2.5%-3.5%, respectively, at an average power of 27.8 dBm across 1.7-2 GHz. For a wideband code-division multiple-access signal across 1.7-2 GHz, the ET PA performs a PAE, an ACLR1, and an ACLR2 of 40%-46.3%, from -39 to -42.5 dBc, and -51 to -58 dBc, respectively, at an average output power of 30.1 dBm. The ET PA with an EDGE signal delivers a PAE, an ACPR1, and an ACPR2 of 37%-42%, from -56.5 to -59.3 dBc, and -63.5 to -69.5 dBc, respectively, at an average power of 28 dBm across the 300-MHz BW. These results show that the proposed design achieves highly efficient and linear power amplification for multimode/multiband wireless communication applications.

Concurrent dual-band SiGe HBT power amplifier for Wireless applications

This paper presents an investigation of a concurrent low-cost dual-band power amplifier (PA) fabricated in SiGe technology, able to simultaneously operate at two frequencies of 2.45 and 3.5-GHz, including an evaluation of its system level performance potentiality. Taking into account the technology novelty and the lack of device characterization and modeling, a hybrid (MIC) approach has been adopted both for a fast prototyping of the PA and for the evaluation of the device potentiality based on an extensive linear and nonlinear characterization. The comparison of PA performance in single-band or concurrent mode operation will be presented. In particular, the measured PA prototype shows an output power of 17.2 and 17-dBm at a 1-dB compression point, at 2.45 and 3.5-GHz, respectively, for CW single-mode operation, with a power added efficiency around 20%. System-level analysis predicts that, when the PA is operated under the 20-MHz Orthogonal Frequency-Division Multiplexing (OFDM) concurrent signals, the maximum output power levels to maintain the Error Vector Magnitude (EVM) within 5% are 11 and 3.5-dBm at 2.45 and 3.5-GHz, respectively. Moreover, new concepts and possible new system architectures for the development of the next generation of the multi-band transceiver front-end will be provided with an extensive system-level evaluation of the amplifier.

A 3~5 GHz UWB Up-Mixer Block Using 0.18-μm CMOS Technology

This paper presents a direct-conversion I/Q up-mixer block, which supports <TEX>$3{\sim}5$</TEX> GHz ultra-wideband(UWB) applications. It consists of a VI converter, a double-balanced mixer, a RF amplifier, and a differential-to-single signal converter. To achieve wideband characteristics over <TEX>$3{\sim}5$</TEX> GHz frequency range, the double-balanced mixer adopts a shunt-peaking load. The proposed RF amplifier can suppress unwanted common-mode input signals with high linearity. The proposed direct-conversion I/Q up-mixer block is implemented using <TEX>$0.18-{\mu}m$</TEX> CMOS technology. The measured results for three channels show a power gain of <TEX>$-2{\sim}-9$</TEX> dB with a gain flatness of 1dB, a maximum output power level of <TEX>$-7{\sim}-14.5$</TEX> dBm, and a output return loss of more than - 8.8 dB. The current consumption of the fabricated chip is 25.2 mA from a 1.8 V power supply.

A 0.13μm CMOS UWB RF Transmitter with an On-Chip T/R Switch

This paper presents a fully integrated 0.13 μm CMOS MB-OFDM UWB transmitter chain (mode 1). The proposed transmitter consists of a low-pass filter, a variable gain amplifier, a voltage-to-current converter, an I/Q up-mixer, a differential-to-single-ended converter, a driver amplifier, and a transmit/receive (T/R) switch. The proposed T/R switch shows an insertion loss of less than 1.5 dB and a Tx/Rx port isolation of more than 27 dB over a 3 GHz to 5 GHz frequency range. All RF/analog circuits have been designed to achieve high linearity and wide bandwidth. The proposed transmitter is implemented using IBM 0.13 μm CMOS technology. The fabricated transmitter shows a -3 dB bandwidth of 550 MHz at each sub-band center frequency with gain flatness less than 1.5 dB. It also shows a power gain of 0.5 dB, a maximum output power level of 0 dBm, and output IP3 of +9.3 dBm. It consumes a total of 54 mA from a 1.5 V supply.

Pronostic des dysautonomies idiopathiques avec hypotension orthostatique

Radio frequency (RF) and microwave power amplifiers using divider–combiner architecture are important blocks of rapidly developing middle and high power RF and microwave systems used in radars, communication, directed energy, electronic warfare, air traffic control, and scientific facilities such as particle accelerators. Many of these amplifiers need to operate in a wide dynamic range of output power levels. For conventional amplifiers that significantly reduces actual efficiency compared to the maximum efficiency attainable at maximum output power levels. Efficiency of a high power amplifier system can be made close to efficiency of a single amplifying module at compression if graceful degradation performance is dramatically improved. The approach is based on dynamic switching on and off some of the amplifying modules, and switchable termination of the corresponding ports of a reactive combiner with externally controlled phasing. The power-scalable method is validated with simulations demonstrating capability of power dynamic range exceeding 13 dB at nearly saturated efficiency of the active power modules and low insertion loss imposed by the passive RF components.

A 3-V monolithic SiGe HBT power amplifier for dual-mode (CDMA/AMPS) cellular handset applications

A dual-mode (CDMA/AMPS) power amplifier has been successfully implemented by using a monolithic SiGe/Si heterojunction bipolar transistor (HBT) foundry process for cellular handset (824-849 MHz) applications. The designed two-stage power amplifier satisfies both CDMA and AMPS requirements in output power, linearity, and efficiency. At V/sub cc/=3 V,the power amplifier shows an excellent linearity (first ACPR<-44.1 dBc and second ACPR<-57.1 dBc) up to 28 dBm of output power for CDMA applications. Under the same bias condition, the power amplifier also meets AMPS handset requirements in output power (up to 31 dBm) and linearity (with second and third harmonic to fundamental ratios lower than -37 dBc and -55 dBc, respectively). At the maximum output power level, the worst power-added efficiencies (PAEs) are measured to be 36% for CDMA and 49% for AMPS operations. The power amplifier also tolerates severe output mismatch (VSWR>12:1) up to V/sub cc/=4 V, with spurs measured to be <-22 dBc in CDMA outputs at two specific tuning angles, but with no spur in AMPS outputs at any tuning angle.

A 780 nm high-power and highly reliable laser diode with a long cavity and a thin tapered-thickness active layer

Conventional AlGaAs laser diodes with uniform thickness active layers of various cavity lengths are investigated. It is recognized that the extension of the cavity length is effective in the improvement of the maximum output power, the temperature characteristics, and the operating life in high-temperature conditions. A 780-nm, high-power laser diode having a 350- mu m-long cavity with a thin tapered-thickness active layer was fabricated. The optical power density near the mirror facets, the thermal resistance, the current density, and the carrier density were reduced by this structure. The laser emitted over 100 mW of CW (continuous-wave) output power at temperatures up to 80 degrees C. A maximum output power level of 160 mW was achieved at room temperature. The fundamental transverse mode was confirmed at least up to 120 mW. >

Multi-layer epitaxially grown silicon impatt diodes at millimeter-wave frequencies

Complementary (N+PP+) and double-drift (N+NPP+) silicon IMPATT diodes were prepared and investigated as oscillators in the millimeter-wave frequency region of 50 to 70 GHz. All the diodes were fabricated from multi-layer epitaxially grown silicon structures. A maximum CW output power level of 198 mW at 62.9 GHz and a maximum conversion efficiency of 7.3% have been measured for the complementary diodes. The double-drift IMPATT diodes have a maximum CW output power of 400 mW at 56.3 GHz and a maximum conversion efficiency of 8.5%.

Performance of P-type epitaxial silicon millimeter-wave IMPATT diodes

A series of p-type IMPATT diodes (p <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> pn <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> ) have been fabricated from epitaxially grown silicon for operation as oscillators at K <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</inf> -band frequencies. A maximum CW output power level of 700 mW at 29.6 GHz, a maximum conversion efficiency of 10.9 percent, and a minimum FM noise parameter, M, of 25 dB have been measured on this series of p-type diodes. A diode oscillating in a variable height radial disk cavity was frequency tuned from 27.5 to 40 GHz, covering the entire K <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</inf> -band, with a 1.4 dB power variation over the tuning range. The minimum CW output power of this tunable oscillator was 360 mW at 6.5 percent efficiency.